The present invention relates generally to marine jet propulsion units, and specifically to relatively higher-powered, inboard mounted marine jet propulsion units having indirect drive systems, and designed for installation in conventional, multipassenger watercraft.
Conventional marine jet propulsion units are intended to replace propeller driven outboard or inboard marine motors. Some of the more significant advantages of jet propulsion units include the lack of a depending gear case, which allows the craft to make tight turns while maintaining the boat in a generally horizontal or level orientation. Another feature of marine jet propulsion units is that the lack of a depending propeller enables the craft to be operated in shallower water without fouling.
An important design consideration of marine jet propulsion units is that operational vibrations should be minimized or eliminated as much as possible to make boating in a watercraft powered by such a unit as pleasant an experience as possible. Unwanted vibrations in such units are generated by two main sources, the power head and the jet pump, the latter component enclosing the transmission which emits vibration from the gears.
Accordingly, a first object of the present invention is to provide a marine jet propulsion unit wherein a significant proportion of operational Vibrations are absorbed instead of being transmitted to the watercraft.
Another object of the present invention is to provide a mounting system for a marine jet propulsion unit including a power head having a vertical crankshaft and a pump unit, wherein the power head is vibrationally isolated from the pump unit.
Yet another object of the present invention is to provide a marine jet propulsion unit wherein power head vibrations are absorbed prior to transmission to the pump unit.